There is a lot of conjecture. There is an old rumor of an OTA update for the Eris for January 22 which seems reasonable considering the updates that were on the same memo concerning the late December update which happened pretty much right on schedule except for starting a few days early to finish on that date. If that is still accurate it should be starting roll out soon cause it will be hitting more devices. The conjecture was that was the date the Eris would be getting 2.0.1 but when the rumors about 2.0.1 got replaced with 2.1 excitement there was nothing to go on but that rumor from Early December.
So does anyone know for sure. Verizon, HTC, and Motorola probably have a pretty good idea. The Eris being an HTC device will not get a lot of good rumors. HTC has very tight lips and we don't get very good rumors about their devices. We are left to vague conjectures and guessing and all we get is occasionally photos of some mysterious phone or software running on a phone and no explaination.